1. Field of the Invention
The present invention relates to a waterproof connector for the electrical connection of a flexible substrate, and more particularly to a waterproof connector for a flexible substrate that provides a waterproof connection.
Priority is claimed on Japanese Patent Application No. 2008-005663, filed Jan. 15, 2008, and Japanese Patent Application No. 2008-307445, filed Dec. 2, 2008, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Conventionally, application of flexible substrates to vehicles has been increasing. In such application, it is required to connect a flexible substrate to a conductor wire at a single terminal. In the application to the vehicles, it is especially important to protect the connecting section by imparting waterproofness so as to keep a highly-reliable connection. There is therefore a demand for a waterproof connector for a flexible substrate that includes an electrical terminal for interconnection between the flexible substrate and a conductor wire accommodated in an easily assembled case housing so as to provide effective waterproofing.
An exemplary waterproof connector for a flexible substrate of the related art includes a flexible substrate 110, a connection terminal 120 and a housing 130 as shown in FIG. 15. The flexible substrate 110 includes an insulating film 111 on which a conductive pattern 112 is formed. The connection terminal 120, made of a metal material, includes a plate-like joint terminal that is connected to the conductive pattern 112 at a terminal section of the flexible substrate 110. The housing 130 accommodates the connecting terminal 120. In the related art waterproof connector 100, the conductive pattern 112 at the terminal section of the flexible substrate 110 and the joint terminal of the connection terminal 120 are joined by, for example, resistance welding (e.g., series welding) to form a connecting section. The connecting section is sealed with a first resin mold 125. The connecting section is accommodated in a connecting section receiving hole 131 formed in the housing 130 at a base end along a direction into which the connector is fit. The base end of the housing 130 is sealed with a second resin mold 126.
The waterproof connector 100 is obtained in the following manner. A connecting section of the flexible substrate 110 with a connection terminal 120 formed thereon is sealed with the first resin mold 125 consisting, for example, of polyamide hot-melt resin. The connecting section is accommodated in the connecting section receiving hole 131 of the housing 130. Then, the base end of the housing 130 is sealed with the second resin mold 126 consisting of the hot-melt resin similar to that of the first resin mold 125. The waterproof connector 100 can therefore be manufactured collectively in single equipment (e.g., a hot-melt adhesive filling device) while preventing an increase in the processing cost and thus an increase in the manufacturing cost. It is not necessary to provide a wire seal or other material at the terminal of the flexible substrate so as to impart waterproofness. Accordingly, the material costs may also be decreased (see Japanese Unexamined Patent Application, First Publication No. 2002-170627).
In the waterproof connector 100 disclosed in Japanese Unexamined Patent Application, First Publication No. 2002-170627, the connection terminal 120 may be connected with the flexible substrate 110 due to a spring effect of the connecting terminal 120. In this case, if the connecting section is sealed by the hot-melt adhesive, the spring force is eliminated and thus the connection becomes unstable. In addition, the hot-melt adhesive (i.e., the second resin mold 126) is exposed from the housing 130. As a result, an external force acts on the hot-melt adhesive (i.e., the second resin mold 126) during handling of the connector 100. As a result, the hot-melt adhesive may be chipped or otherwise damaged, or adhesion strength between the hot-melt adhesive and the housing 130 may decrease, thereby causing deterioration in the fixing force and waterproofness.